1. Field of the Invention
The present invention relates to a technology for integrating channels of a local area network (hereinafter referred to as LAN) communication apparatus with channels of a telephone apparatus such as terminal devices and exchanges, more particularly to an integrated transmitter for the LAN communication equipment with the telephone apparatus, a telephone apparatus and a LAN communication equipment which are connected to a coaxial cable or a twisted pair line of the LAN and transmit phone signals and LAN data simultaneously, and a communication method for transmitting the phone signals and the LAN signals.
2. Description of the Prior Art
Computer telephony and IP telephony for achieving a high efficiency in business by simultaneous use of the LAN and the telephones has been put into a practical use with a development of the Internet. In the communication telephony and the IP telephony, actual communication contents themselves must be integrated, and software for integrating them must be installed in computer communication terminal devices.
On the other hand, there have been client""s needs to integrate the LAN with the telephones while using a conventional communication system still within an enclosure such as a building. Offering of goods to meet their needs has been desired.
In U.S. Pat. No. 5,896,389, an integrated transmitter in which LAN and telephones are integrated by a common transmission line is disclosed. To be more specific, the following technology is disclosed. A transducer is connected to each terminal of two pairs of twin lines which connect the LAN and the telephones. LAN signals are sent out from both terminals of the transducer and telephone signals are sent out in-phase using a center tap of the transducer. Thus, the pair of twin lines is used for simultaneously transmitting the telephone signals and the LAN signals, thus realizing the integration of the LAN and the telephone by a common transmission line.
According to the above mentioned integrated transmitter, signal lines for the LAN and telephone lines are integrated to one transmission line, that is, a pair of twin lines, so that the number of lines can be reduced. In addition, the technology disclosed in the integrated transmitter has a merit that the conventional LAN communication equipment and telephone communication apparatus are still used and the LAN signals and the telephone signals can be simultaneously transmitted. Therefore, this technology is capable of constructing an economic system.
However, in the technology disclosed in the U.S. Pat. No. 5,896,389, telephone signals are supplied to the center tap of the transducer, and the telephone signals are fetched out from the center tap. Thus, the telephone signals are transmitted as identical in-phase signals. Accordingly, a precision of the center tap of the transducer is required, and a more expensive transducer compared to a transducer with a center tap on the market is needed. At least two pairs of two lines are necessary.
Furthermore, because of a transducer superposing/separating circuit for superposing the telephone signal supplied to the center tap of the transducer on the LAN signal and for separating the telephone signal and the LAN signal from the transducer, there is a limitation to a high speed processing.
A first object of the present invention is to provide an integrated transmitter and a communication method for integrating LAN and telephones without supplying a telephone signal to a center tap of a transducer, that is, without constructing a transducer superposing/separating circuit.
A second object of the present invention is to provide an integrated transmitter and a communication method which are capable of using an inexpensive transducer on the market, which requires no precision of its center tap.
A third object of the present invention is to provide a telephone apparatus and a LAN communication equipment which are connected either to the coaxial cable or to the twisted pair line of the LAN and capable of integrally transmitting the telephone signal and the LAN data, can be provided.
An integrated transmitter of the present invention comprises a first signal distribution circuit for distributing a LAN signal into first and second signals, each of which has an absolute value equal to each other; a second signal distribution circuit for distributing a telephone signal into third and fourth signals, each of which has an absolute value equal to each other; a transmission line having two lines which transmit individually the first and third signals and the second and fourth signals; and a receiving circuit for detecting a receiving circuit for detecting at least one of the LAN signal and the telephone signal by adding one of the signals to the other signal, transmitted on each of the two lines, or subtracting one of the signals from the other signal, transmitted on each of the two lines.
An integrated transmitter of the present invention comprises a transmission circuit for distributing a LAN signal into first and second signals, each of which has an absolute value equal to each other, for distributing a telephone signal into third and fourth signals, each of which has an absolute value equal to each other, and for sending out individually the first and third signals and the second and fourth signals onto two lines of a transmission line; and a receiving circuit for detecting a receiving circuit for detecting at least one of the LAN signal and the telephone signal by adding one of the signals to the other signal, transmitted on each of the two lines, or subtracting one of the signals from the other signal, transmitted on each of the two lines.
A communication method of a telephone signal and a LAN signal of the present invention comprises the steps of: distributing a LAN signal into first and second signals, each of which has an absolute value equal to each other; distributing a telephone signal into third and fourth signals, each of which has an absolute value equal to each other; sending out individually the first and third signals and the second and fourth signals onto two lines of one transmission line; and detecting a receiving circuit for detecting at least one of the LAN signal and the telephone signal by adding one of the signals to the other signal, transmitted on each of the two lines, or subtracting one of the signals from the other signal, transmitted on each of the two lines.
According to the integrated transmitter and the communication method, since the telephone signal is superposed on the LAN signal on the line used in the conventional LAN, a telephone communication can be integrated into a communication using a line of LAN. Furthermore, the LAN signal and the telephone signal are integrated with each other without supplying the telephone signal to a center tap of a transducer, that is, without constructing a transducer superposing/separating circuit, and the telephone signal can be superposed on the LAN signal on the line of LAN. Thus, a communication speed is made to be high, and use of a telephone line is made to be unnecessary.
A LAN communication equipment of the present invention is the one which is connected to an integrated transmitter having a transmission circuit for distributing a LAN signal into first and second signals, each of which has an absolute value equal to each other, for distributing a telephone signal into third and fourth signals, each of which has an absolute value equal to each other, and for sending out individually the first and third signals and the second and fourth signals onto two lines of a transmission line. The LAN communication equipment has a feature in that a receiving circuit for adding or subtracting the signals individually transmitted on the two lines of the transmission line to detect either the LAN signal or the telephone signal, the data processing circuit 31 for receiving the LAN signal detected by the receiving circuit and for performing the data processing for the detected LAN signal, and an interface (telephone interface 41) for supplying the telephone signal detected by the receiving circuit to the outside.
Another LAN communication equipment of the present invention is the one which is connected to an integrated transmitter having a transmission circuit for distributing a LAN signal into first and second signals, each of which has an absolute value equal to each other, for distributing a telephone signal into third and fourth signals, each of which has an absolute value equal to each other, and for sending out individually the first and third signals and the second and fourth signals onto two lines of a transmission line, wherein a receiving circuit for detecting the LAN signal by subtracting the second and fourth signals from the first and third signals and for detecting the telephone signal by adding the second and fourth signals to the first and third signals, the second and fourth signals being transmitted one of the two lines of the transmission line and the first and third signals being transmitted onto the other of the two lines of the transmission line; a processing circuit for receiving the LAN signal detected by the receiving circuit to execute a data processing for the LAN signal; and a telephone circuit for executing a telephone communication by the telephone signal detected by the receiving circuit.
With such constitution, it is possible to execute the telephone communication while executing simultaneously the communication for the LAN signal by the LAN communication equipment.
A telephone communication apparatus of the present invention is connected to an integrated transmitter having a transmission circuit for distributing a LAN signal into first and second signals, each of which has an absolute value equal to each other, for distributing a telephone signal into third and fourth signals, each of which has an absolute value equal to each other, and for sending out individually the first and third signals and the second and fourth signals onto two lines of a transmission line. The telephone communication apparatus of the present invention has a feature in that a receiving circuit for detecting the LAN signal by subtracting the second and fourth signals from the first and third signals and for detecting the telephone signal by adding the second and fourth signals to the first and third signals, the second and fourth signals being transmitted one of the two lines of the transmission line and the first and third signals being transmitted onto the other of the two lines of the transmission line; a telephone circuit for receiving the telephone signal detected by the receiving circuit to execute a telephone communication; and an interface for supplying the LAN signal detected by the receiving circuit to the outside.
With such constitution, the telephone communication apparatus is provided, which can execute the telephone communication by connecting the telephone set to the transmission line of the LAN, and further can receive and send the LAN signal.